In delta-star connection, the phase displacement between the primary voltage and secondary emfs is
Show Hint
Whenever you see a mismatch in the primary and secondary connection types (one side is Delta and the other side is Star), the phase displacement will always involve an odd multiple of $30^\circ$ (typically $\pm 30^\circ$). If the connections are identical on both sides (Star-Star or Delta-Delta), the shift is always $0^\circ$ or $180^\circ$.